Electrical conductor.



No. 678,030. Patented July 9, I901.

v E. D. PRIEST.

ELECTRICAL CONDUCTOR.

(Applimtinn filed m 20, 1901.

(No Model.)

v Fig. 3.

I Edward DP Mumps PETERS co. vnomuma. WASHINGYON, u. c

UNITED STATES PATENT OFFICE.

EDWARD D. PRIEST, OF SOHENEOTADY, NEW YORK, ASSIGNOR TO GENERAL ELECTRIC COMPANY, OF NEW YORK.

ELECTRICAL CONDUCTOR.

SPECIFICATION forming part of Letters Patent No. 678,030, dated July 9, 1901.

Application filed May 20, 19 01.

To all whom, it may concern.-

Be it known that I, EDWARD D. PRIEST, a citizen of the United States, residing at Schenectady, county of Schenectady, and State of New York,have invented certain new and useful Improvements in Electrical Conductors, (Case No. 2,093,) of which the following is a specification.

My present invention relates to a form of electrical conductor of particular value in connection with dynamo-electric machines, although useful in other relations as well. The conductor is constructed with a view to reducing the loss due to eddy-currents, which in conductors of solid cross-section is considerable. In dynamo-electric machines the eddy-current. loss is largely due to the fact that as the conductor passes into and out of the magnetic field the variation of flux through one portion of the same is greater than the variation in another portion. Thus with a fiat-bar conductor arranged on edge in a slot the outer edge may pass into the magnetic field before the under edge. A current is thus caused to fiow along the top of the bar and return through the lower edge of the bar. In order to reduce the loss thus occasioned, I split the bar lengthwise, and at proper intervals I transpose the top and bottom portions of the bar, thereby breaking up the circulation of local currents, which would otherwise ensue.

The scope of my invention I will set forth with particularity in the claims appended hereto, while for a more complete understanding of the invention itself reference is to be had to the following description, taken in connection with the accompanying drawings, in which Figure 1 represents an armature-bar made in accordance with my invention; Fig. 2, another view of the same, and Fig. 3 a representation of a railway-motor armature provided with armature-conductors fashioned in accordance with my invention.

Referring to Fig. 1, the armature-conductor will be seen to consist of a strip of metal, preferably copper, split lengthwise for aportion of its length. In forming the conductor the strip is first split in a straight line, as from the point 1 to the point 2. The posi- Serial No. 60.987; (No model.)

tions of adjacent portions of the two parallel strips thus formed are, by suitable mechan ical means, forcibly transposed, as indicated in Fig. 1, in which theportion of the strip between the points'designated as 3 4 is drawn laterally away from its position in line with the portions 5 6, in the process of which the offsets at 3 and 4 are formed. In a similar manner a portion of the opposite strip, which extends in a straight line between the points 7 and 8, is forced into the position covered by the stippled surface 9, which in this case represents a portion of a strip of insulating material placed between the divided portions of the bar to insulate the same from each other. The ofisets on this last-mentioned strip come immediately under those indicated at 3 and 4. At these points where the offsets cross the total cross-section of the conductor would be increased were it not for the fact that the thickness of the offsets is reduced either byrolling or hammering, so that the combined thickness is equal to that of the other portions of the armature-conductor.

Fig. 2 is an edge view of the conductor and shows more clearly the manner in which the offsets overlap. Thus, for example, in this figure the part designated at 6 is the same as that similarly designated in Fig. 1. The strip extending from right to left comprises, first, the sections 6, then that portion of the offset 4 indicated in Fig. 2 at 4, and then the section 10, which is shown in Fig. 1, but which does not appear in Fig.2, since it is located on the opposite edge of the conductor. The strip is completed by means of the offset 3 and the section 5, as will readily be understood.

Fig. 3 shows two conductors such as described in place on a motor-armature, the end connections being cut away for simplicity of illustration. No special description of the arrangement is necessary beyond that already given.

I may observe that the conductor above described is intended to accomplish substantially the same results as are secured by the use of a stranded and twisted conductor heretofore commonly employed. It possesses the valuable advantage, however, that a given cross-section of the same contains a greater actual area of copper than does the stranded conductor, and at the same time it is practically as effective in reducing eddy-currents. Moreover, the offsets or points where the c0nductors or strips cross are purposely widened out where they are thinned, so as to preserve the same cross-section as at other portions of the strips, the offsets making up in width What they lack in thickness. This is clearly indicated in the drawings and constitutes a valuable feature of the invention. Heating of the conductors is therefore not localized at the crossing-points.

My invention is not to be considered as limited to a bar split into strips, but integral at its ends, as described, but includes the characteristics set forth in the appended claims.

What I claim as new, and desire to secure by Letters Patent of the United States, is

1. An electrical conductor consisting of a strip of metal split lengthwise, adjacent portions of the resulting strips being transposed.

2. A conductor consisting ofa strip of metal split lengthwise, and superposed offsets formed at intervals in the length of each component strip.

3. A conductor consisting of strips of metal placed side by side and at intervals transposed in position so that each strip passes from side to side of the resulting conductor.

4:. A conductor consisting of flat strips of metal placed side by side and at intervals in their length transposed from side to side of the resulting conductor.

5. A conductor consisting of flat strips of metal placed side by side and at intervals in their-length transposed from side to side of the resulting conductor, and insulating material interposed between said strips.

6. The combination of flat crossed conductors placed side by side, the crossing portions being made of the same cross-section as at other points in the conductors.

7. The combination of flat crossed conductors placed side by side, the said conductors being of substantially uniform cross-section.

8. The combination of crossed conductors placed side by side, the cross-section of the combined conductors and of each individual conductor being uniform throughout.

9. The combination of crossed conductors placed side by side, the crossing portion 01". each conductor being of reduced thickness but increased Width.

In Witness whereof I have hereunto set my hand this 17th day of May, 1001.

EDXVARD D. PRIEST.

Witnesses:

BENJAMIN HULL, MARGARET E. WooLLnY. 

